AKIS (Acis) was a river-god of eastern Sikelia (Sicily). He was originally a Sikelian (Sicilian) youth loved by the Nereid Galateia whose jealous rival, the Kyklops (Cyclops) Polyphemos, killed him with the cast of a boulder. The gods in pity transformed the dying youth into a river.
The Akis stream flowed down into the Mediterranean from the slopes of Mount Aitna (Etna) near the town of Akion (Acium). Other personified Sikelian rivers included the Symaithos (Symaethus) and Anapos to the south, and Krimisos (Crimisus) in the west.
ACIS (Akis), according to Ovid (Met. xiii. 750, &c.) a son of Faunus and Symaethis. He was beloved by the nymph Galatea, and Polyphemus the Cyclop, jealous of him, crushed him under a huge rock. His blood gushing forth from under the rock was changed by the nymph into the river Acis or Acinius at the foot of mount Aetna. This story does not occur any where else, and is perhaps no more than a happy fiction suggested by the manner in which the little river springs forth from under a rock.
Source: Dictionary of Greek and Roman Biography and Mythology.
CLASSICAL LITERATURE QUOTES
Ovid, Metamorphoses 13. 750 ff (trans. Melville) (Roman epic C1st B.C. to C1st A.D.) :
"Acis was son of Nympha Symaethis and Faunus [Pan] was his father, a great joy to both his parents, and a greater joy to me; for me, and me [the Nereid Galateia] alone, he loved. He was sixteen, the down upon his cheek scarce yet a beard, and he was beautiful. He was my love, but I was Cyclops' [Polyphemos'] love, who wooed me endlessly and, if you ask whether my hate for him or my love for Acis was stronger in my heart, I could not tell; for both were equal. Oh, how powerful kind Venus [Aphrodite], is thy reign! That savage creature . . . now felt pangs of love, burnt with a mighty passion, and forgot his flocks and cares . . . There juts into the sea a wedge-shaped point, washed by the ocean waves on either side. Here Cyclops climbed and at the top sat down, his sheep untended trailing after him. Before him at his feet he laid his staff, a pine, fit for the mainmast of a ship, and took his pipe, made of a hundred reeds. His pastoral whistles rang among the cliffs and over the waves; and I behind a rock, hidden and lying in my Acis' arms, heard far away these words and marked them well.
‘Fair Galatea [the Cyclops woos her with boasts of his attributes.] . . . Oh, I could bear your scorn more patiently did you but spurn all others, but, if Cyclops you reject, why prefer Acis, Acis' arms to mine? Acis may please himself and please, alas, you Galatea. Give me but the chance, he'll find my strength no smaller than my size. I'll gouge his living guts, I'll rend his limbs and strew them in the fields and in the sea--your sea, so may he be one flesh with you! I burn! The fire you fight is fanned to flame; all Aetne's furnace in my breast I bear, and you, my Galatea, never care!’
Such was his vain lament; then up he rose (I saw it all) as a fierce thwarted bull roams through the woodlands and familiar fields, and, spying in his rage Acis and me, all unaware and fearing no such fate, shouted ‘I see you; now I shall make sure that loving fond embrace shall be your last.’ Loud as an angry Cyclops ought to shout he shouted; Aetna shuddered at the din. Then I in panic dived into the sea beside us; the hero Symaethius [Acis] had already turned his hero's back and shouted as he fled ‘Help, Galatea! Father, mother, help! Admit me to your kingdom for I die.’ Cyclops pursued and hurled a massive rock, torn from the hill, and though its merest tip reached Acis, yet it crushed and smothered him. But I (it was all the Fates permitted me) caused Acis to assume his ancestral powers [i.e. he was a a grandson of the River Symaethus]. Beneath the rock came trickling crimson blood, and soon the ruddy hue began to fade, and turned the colour of a swollen stream after the first rain falls, and in a while it cleared. Then in the rock a crack split wide and in the fissure rose a tall green reed, and from the hollow opening came the sound of waters leaping forth, and suddenly--most wonderful!--there stood a youth waist deep with woven rushes round his new-sprung horns; and he, though larger and his face wave-blue, was surely Acis--Acis there himself, changed to a River-God (Numen Flumina); and still the same his waters keep that legendary name."
- Ovid, Metamorphoses - Latin Epic C1st B.C. - C1st A.D.
Other references not currently quoted here: Servius on Virgil's Eclogues, et. al.